What conclusion can be drawn from a 10 mm area of induration after a PPD test?

A 10 mm area of induration following a PPD (Purified Protein Derivative) test is indicative of a positive reaction, suggesting that the individual has been exposed to the tubercle bacillus, which is the bacteria that causes tuberculosis (TB). This reaction demonstrates that the immune system has recognized the proteins from the bacteria, which typically occurs when someone has either been infected with TB in the past or has received the vaccine.

It is important to understand that a positive result does not confirm that the individual has active clinical tuberculosis. Instead, it signifies prior exposure. This distinction is critical; individuals with a positive PPD result may require further evaluation, such as a chest X-ray or sputum test, to determine if they have latent tuberculosis infection (LTBI) or active TB disease.

The other options do not correctly represent the implications of a 10 mm induration. While clinical tuberculosis, passive immunity, and resistance to the tubercle bacillus are related concepts, they do not accurately describe the specific conclusion that can be drawn from the test result in question. Therefore, the interpretation that the client has been exposed to the tubercle bacillus is the most accurate conclusion based on the PPD test results.